Java - DTracing Java
These scripts trace the JVM, and require the Java hotspot provider which
was shipped with Java starting with version 1.6.0.
Some of these scripts measure method and object events, and require
the Java process to be run using the "+ExtendedDTraceProbes" flag.
For example,
java -XX:+ExtendedDTraceProbes classfile
The ExtendedDTraceProbes flag is not on by default to avoid the additional
overhead for maintaining these additional probes. When this flag is
enabled, the JVM may execute slightly slower than before; when the probes
are also enabled (especially method probes), the JVM may execute
significantly slower.